Slide glass mechanism and seal system for vehicular backlite

ABSTRACT

A window frame assembly is provided with a sliding glass mechanism and seal system for vehicular backlites. The assembly includes a pair of fixed side windows secured in a frame in spaced-apart relationship, and one or more sliding windows positioned in channel brackets to close and open the aperture between the fixed window panes. A single gasket formed by a reaction injection molding process is formed around the periphery of the window assembly for mounting the window assembly in the opening of a body panel of a pickup truck. The gasket is integrally formed about the aperture during the reaction injection molding process and includes a flexible lip to engage the sliding window. The sliding window slides in the channels of the channel brackets and is positioned to engage the lip of the gasket to seal the aperture. The required sliding force to open and close the sliding window may be reduced by spring loading the sliding window in the channel. Channel guides with a spring mechanism are placed on the top and bottom edges of the sliding glass. A cam formed in the channel bracket is used to compress the springs and force the sliding glass window against the lip of the gasket to sealingly close the aperture. When the sliding window is in the range of open positions, the spring mechanism clears the cam and forces the sliding window away from the lip of the gasket to facilitate sliding of the glass.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to window frame assemblies, and inparticular, to an assembly having a sliding glass mechanism and sealsystem for vehicular backlites. The assembly includes a frame formounting the assembly in a vehicle, a pair of fixed side window panessecured in the frame, and one or more sliding window panes slidinglypositioned between the fixed window panes.

2. Summary of Related Art

Pickup trucks and other related vehicles have a rear window, orbacklite, that is mounted in an opening in the body panel immediatelybehind the seats in the passenger compartment. The backlites aresupplied to the pickup truck manufactures as window frame assemblies forinstallation on the assembly line. The backlite assemblies typicallyinclude a metal frame, such as aluminum, provided with a top and bottomchannels to facilitate the sliding of the glass panels.

The backlite assembly is mounted directly into the window opening in thebody panel. The assembly is secured to the body panel with adhesivesand/or mechanical fastener devices. A urethane adhesive is frequentlyused in the backlite applications, such adhesive being applied to themounting surface of either the opening in the body panel or the backliteassembly prior to the moment at which these two structures are broughtinto abutment.

The backlite assembly in a pickup truck can be a source of problems,such as water leakage. The leakage may occur at the engagement of thebacklite assembly and the body panel, which is typically caused byimproper adhesive application or frame distortion. Water leakage mayalso occur around the seal extending about the four edges of theaperture in a sliding window. Two edges of the aperture are formed bythe top and bottom channel. The other two edges are formed the internaledges of the fixed, side windows (or a pillar mounted thereon). A tightseal is required on all four edges of the sliding window to ensure theintegrity of the seal.

The primary configuration currently used in the backlite assembliesconsists of an assembly having a metal bracket with two channelsextending around the complete perimeter of the assembly. The two fixedwindows are mounted in an outer channel in planar, spaced-apartrelationship with two horizontal and two vertical seals secured in theouter channel surrounding the opening between the fixed windows. Thesliding window is disposed in the inner channel, adjacent the fixedwindows. In the closed position, the sliding window sealably engages theseals to seal the opening between the fixed windows. When moved to anopen position, the sliding window slides in the internal channel tooverlap one of the fixed windows in the outer channel.

The seals are made from rubber or other equivalent material and includean extended lip which flexibly engages the sliding window to preventwater and dirt from entering around the sliding window. The rubber sealsare mounted in the outer channel between the two fixed windows. Therubber seals facilitate the sliding of the sliding window in ahorizontal direction while maintaining sufficient pressure at the lip ofthe seal to prevent water from leaking around the seal to the interiorof the assembly and the pickup truck.

The rubber seals require a manual production step to properly installthe seals around the opening of the assembly. One of the needs of thewindow manufacturers is to find an alternative sealing system whichseals the opening without discrete rubber seals, thereby reducingmaterial and labor costs during production operations and whileimproving the integrity of the seal around the sliding window.

Although rubber seals are expensive and difficult to install, suchrubber seals may still be required or preferred in certain embodiments.If the rubber seals are not installed properly, then water leakage mayoccur in the horizontal channels or along the vertical edges of theaperture. An improved method, such as encapsulation, for securing therubber seal about the aperture in the backlite is also desired in theindustry.

In addition to the sealing problem noted above, there are severaladditional performance requirements which often present problems in theuse of the sliding window assemblies in pickup trucks. In the closedposition, the backlite window assembly must maintain the wind and roadnoise within acceptable limits. The seal must uniformly seal the slidingwindow to eliminate outside noise. The channel drain holes and otherdesign features must be designed to eliminate road noise problems.

High or variable sliding force is another concern in backlite windowassemblies. The sliding window typically includes rubber or plasticguides to secure the slidable window within the bottom internal channel.The slidable window should slide freely within the guides while stillbeing positioned to sealably engage the lip of the rubber sealingmember. If the seals are installed improperly, such as misalignment,then the sliding window may difficult to slide. The channels of theframe may also be misaligned. The sliding characteristics of the rubberseals and the channel guides should permit the sliding of the slidingwindow while maintaining the necessary seal force between the slidingwindow and the seal.

Another problem which frequently occurs with backlite assemblies is asliding glass rattle. When the sliding glass is moved to an openposition, the sliding glass in the internal channel must be retained bychannel guides in order to prevent a rattle of the glass.

In summary, a backlite assembly with one or two sliding windows mustmaintain a proper seal to eliminate water leaks and wind/road noise in aclosed position. The slidable windows, without compromising the requiredseal, must be easy to slide to facilitate the opening and closing of thebacklite sliding window. In the open position, the sliding window mustbe secured in the channel to prevent a rattle of the glass.

In a backlite assembly, the required features include a tight seal and,conversely, easy sliding movement. Adhesives are used to secure thebacklite assembly in the pickup truck and to secure the rubber seals andthe guides in the assembly. Slip coats and other lubricants are oftenused to facilitate the sliding of the sliding glass against the seal andthe guide walls. Applying adhesives and lubricants in such proximity onthe same assembly adds to the production costs and could cause qualityproblems if either is applied improperly.

A window frame assembly for pickup truck backlites is disclosed in U.S.Pat. No. 5,294,168 to Kronbetter. The Kronbetter window assemblyincludes a complex top and bottom rail with two channels, an outerchannel for mounting the two outer pieces of fixed glass and the rubbersealing members, and an inner channel for securing the guides and thesliding windows.

In Kronbetter, the assembly of the window frame starts with theinsertion of the guides into the inner channels. Adhesive is applied tothe outer channel to secure the fixed window panes in the frame. Thesliding window panes are inserted into the guides and the bottom metalframe segment and the bowed, top metal frame segment are welded orotherwise bonded together. The sealing members are then placed in theouter channel of the frame to slidably and sealably engage the slidingwindows in the inner channel. The window frame assembly is then readyfor installation into a pickup truck.

The metal frame of the window assembly in Kronbetter is expensive tomanufacture and assemble. Pickup truck manufacturers desire a lessexpensive window assembly that is easier to mount and still meets all ofthe performance requirements.

In recent years, motor vehicle glass suppliers have been supplying tomotor vehicle manufactures, modular windows having urethane gasketsmolded in situ by means of a reaction injection molding (RIM)encapsulation process. These gaskets encapsulate the peripheral edge ofthe glass window and provide an effective seal between the glass and thewindow opening in the metal automobile body. The gasket is formed byinserting a glass sheet in a suitable mold and injecting a liquid,plastic forming composition about the periphery thereof whichpolymerizes and cures in contact with the glass and tightly adheresthereto.

Prior to the development of the reaction injection molding process,vehicle window assemblies were comprised of a plurality of elements,including adhesive sealants applied around the marginal edges of theglass sheet, suitable mechanical fasteners such as metal clips, andexterior decorative trim strips disposed to cover the junction betweenthe marginal edges of the glass sheet and the adjacent portion of thevehicle frame. These structures were costly in both material and labor,and were very difficult (if not impossible) to install using robotics.In order to install the windows using robotics, it was necessary thatthe windows have a gasket formed around the perimeter thereof.

The initial vehicular window gaskets were formed from a molded plasticmaterial, such as polyvinyl chloride. The relatively high pressurerequired for the PVC injection molding process, however, resulted inglass breakage and other production related problems. The PVC windowassembly process is described in U.S. Pat. No. 4,072,340 to Morgan.

In the 1980's, the reaction injection molding encapsulation process wasdeveloped to produce modular windows which would reduce glass breakageand facilitate the installation of motor vehicle windows by robots. U.S.Pat. No. 4,561,625 to Weaver describes the use of polyurethane molded onthe peripheral edges of the glass at low pressures through the use of aRIM technique. The polyurethane gasket was of great significance sinceit eliminated the need for the conventional adhesive sealants, ancillarymetal clips and exterior decorative trim strips disposed to cover thejunction between the marginal edges of the glass sheet and the adjacentportions of the vehicle frame. The RIM encapsulated gasket worked betterthan the polyvinyl chloride gasket which was then being contemplated foruse, in that the RIM method of forming the gasket permitted it to bedone at lower pressures and accordingly substantially reduced theincidents of breakage of the glass.

U.S. Pat. No. 4,755,339 to Reilly et al. and U.S. Pat. No. 4,839,122 toWeaver disclose further details regarding the method and apparatus forreaction injection molding of window gaskets.

Metal brackets and spacers have been incorporated into the reactioninjection molding process to improve the functionality of the glass.U.S. Pat. No. 4,662,113 to Weaver shows a window assembly used for doorwindows on motor vehicles which is operated in a vertical manner. Abracket is placed in the mold with the window glass and is integrallysecured to the window glass during the formation of the gasket by therim injection molding process. The bracket provides a means to connect alinkage or other drive means to the window glass to raise and lower thewindow in the motor vehicle.

U.S. Pat. No. 4,951,927 to Johnston et al. shows a spacer element usedto maintain spacing between two sheets of glass. The spacer ispositioned about the periphery of the sheets of glazed glass prior topositioning the glass in a mold for reaction injection molding to forman encapsulating gasket around the peripheral edge portions to produce amultiple glazed structure.

Because of the desirable features of the gaskets formed by reactioninjection molding, the process has been used for several additionalapplications. U.S. Pat. No. 5,060,440 to Weaver discloses two glasssheets flexibly connected by adjacent gaskets joined during the reactioninjection molding process. U.S. Pat. No. 4,996,808 to Weaver disclosesan encapsulated window assembly in which a preformed sheet of plasticmaterial is place in the mold prior to the gasket forming process.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a windowframe assembly provided with a sliding glass mechanism and seal systemfor vehicular backlites. The assembly includes a pair of fixed sidewindow panes secured between two brackets in parallel, spaced-apartrelationship, and one or more sliding windows slidingly positioned inthe bracket channels to close and open the aperture between the fixedwindow panes.

The window frame assembly includes a pair of linear channel bracketswhich form the top and the bottom of the assembly. The fixed sidewindows, two generally rectangular pieces of glass, are secured to theouter faces of the channel brackets by a reaction injection moldingprocess, which forms a polyurethane gasket on the periphery of the totalassembly. The fixed side windows are spaced apart to define an aperturewhich is opened and closed by a sliding window. The channels in the topand bottom channel brackets are inwardly facing channels for securingthe sliding window.

The polyurethane gasket formed around the periphery is used for mountingthe window assembly in the opening in the body panel of the pickuptruck. The gasket provides a flush surface for improved sealing of theopening in the body panel.

During the reaction injection molding process, a single gasket is formedaround the periphery of the window assembly plus on the two verticalinternal edges of the fixed side window glass. Consequently, theaperture between the two fixed pieces of glass has a unitary, RIMencapsulated gasket on all four sides of the aperture. The single gasketincludes horizontal gasket segments formed on the top and bottom channelbrackets and the vertical gasket segments formed on the internalvertical edges of the fixed side window glass to define an aperture.

The gaskets about the aperture are formed with a flexible lip tosealably engage the sliding window, which may eliminate the need for aseparate rubber sealing member. The sliding window slides in thechannels of the channel brackets and is positioned to the lips of thegasket to seal the aperture. If sufficient force can be maintained bythe sliding glass on the lip of the channel, the need for an internalrubber sealing member is eliminated. The elimination of the sealingmember, which is relatively expensive to make and install, is ofsignificant benefit to window assembly manufacturers.

However, the application of sufficient force to provide a sealedengagement generally restricts the sliding motion of the sliding windowin the channels. The required sliding force may be reduced by applying alubricant on the lip of the urethane gasket or by coating the edges ofthe sliding window.

An additional means for reducing the sliding force is to spring load thesliding glass window in the top and bottom channel. A spring loadedglass guide may be place on the corners of the top and bottom edges ofthe sliding window. The spring arm of the guide forces the slidingwindow away from the lip of the gasket when the window is in the rangeof open positions to facilitate sliding of the glass. A cam formed inthe channel bracket or other similar mechanism may be used to compressthe springs and force the sliding glass window against the lip of thegasket to sealingly close the aperture in the closed position.

An object of the present invention is to eliminate the requirements fora discrete sealing member to be mounted about the aperture in the windowassembly to prevent water leaks. The lip of the outer seal around theperiphery of the assembly can be designed to sealably engage the sliderwindow without the sealing member, thereby reducing the cost of thewindow assembly.

In circumstances where a discrete sealing member is still required, thesealing member may be secured around the aperture of the backliteassembly by the gasket formed during the reaction injection moldingprocess. The lip for sealably engaging the sliding window is formed inthe sealing member. The polyurethane gasket secures and seals the fixedside windows, the brackets and the rubber seal to form an windowassembly in a single reaction injection molding process.

An object of the present invention is to simplify the production processand improve the seal quality in a backlite assembly. The gasket formedduring the reaction injection molding process secures the componentparts in the desired position and forms the seal around the aperture ofthe backlite. In an alternative embodiment, the gasket secures adiscrete sealing member about such aperture. In either embodiment, theseal about the aperture is improved by the gasket, which can be formedin a single reaction injection molding process step.

A further object of the present invention is to simplify the metal framerequired for the backlite window assembly and to minimize the assemblycosts. By using reaction injection molding to form a gasket around theperiphery for mounting the window assembly in a body panel, the need fora metal frame is eliminated except to provide a frame to connect the twofixed pieces of window glass, and to provide a channel for positioningthe sliding glass window. A "U" or "L" shaped channel bracket extendingbetween the top and bottom edges of the fixed glass windows along thehorizontal path of the sliding window is the primary requirement.

An additional object of the present invention is to provide a slidingmechanism which makes the sliding window relatively easy to slide andwhich does not rattle when the window of the backlite window assembly isopen. Mounting the sliding window in the channel with spring loadedglass guides separates the sliding window from the gasket in the openposition, and a cam device causes the sliding window to sealingly engagethe gaskets in the closed position.

BRIEF DESCRIPTION OF THE DRAWINGS

The above, as well as other advantages of the present invention, willbecome readily apparent to those skilled in the art from the followingdetailed description of a preferred embodiment when considered in thelight of the accompanying drawings in which:

FIG. 1 is a front elevational view of the backlite window assembly for amotor vehicle, such as a pickup truck, as viewing the window assemblyfrom inside the pickup truck;

FIG. 2 is a perspective view of the top and bottom channel brackets andthe fixed side pieces of glass prior to being placed in a mold forreaction injection molding of the urethane gasket around the peripheryof the such parts;

FIG. 3 is a perspective view of the piece of sliding glass with guidesmounted on the top and bottom corners, prior to insertion into thechannels of the brackets;

FIG. 4 is a top view and FIG. 4A is a perspective view of the slidingwindow guides with a spring portion formed on the guides;

FIG. 5 is a front elevational view of the handle mechanism used to open,close, and slide the sliding window;

FIG. 6 shows a slot in the bottom bracket for inserting the slidingwindow into the channel of the bracket;

FIG. 7 is an enlarged fragmentary sectional top view of the windowassembly in FIG. 1 taken along the line 7--7 thereof;

FIG. 8 is an enlarged fragmentary sectional side view of the windowassembly in FIG. 1 taken along the line 8--8 thereof;

FIG. 9 is an enlarged sectional side view of the top bracket showing thegasket, sliding window, and window guide in the closed position;

FIG. 10 is an enlarged sectional side view of the bottom bracket showingthe gasket, sliding window, and window guide in the closed position;

FIG. 10A is enlarged sectional side view of a bottom bracket showing analternative embodiment having a different lip configuration on thegasket, a narrower bracket, and modified window guide in the closedposition;

FIG. 11 is a fragmentary view of the bottom bracket showing thepositioning of the cam and the window guide when the sliding window isin a closed position;

FIG. 12 is top plan view of the bottom bracket fragment in FIG. 11 takenalong the line 12--12 thereof;

FIG. 13 is the top plan view of the bottom bracket shown in FIG. 11after the sliding window has been moved to an open position;

FIG. 14 shows a discrete sealing member, such as a rubber seal, which issecured about the aperture in the backlite window assembly in anadditional embodiment;

FIG. 15 is a top plan view of the bottom bracket fragment of a windowassembly which includes the discrete sealing member shown in FIG. 14,and shows the positioning of the rubber seal when the aperture isclosed; and

FIG. 16 is a sectional side view of the bottom bracket of the windowassembly with discrete sealing member, FIG. 16 showing the gasket, thesealing member, sliding window, and window guide in the closed position.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, there is shown a backlite window assembly 14according to the present invention, ready for installation into anopening in a body panel of a motor vehicle, such as a pickup truck. Thebacklite window assembly 14 includes a bottom channel bracket 16, a topchannel bracket 18, a pair of laterally spaced, fixed windows 20, 22 anda single sliding window 24. With a single sliding window 24, a sidelatching mechanism 40 is used. In the alternative, a pair of slidingwindows with a center latching mechanism can be used in the backlitewindow assembly 14.

The backlite window assembly 14 also includes a single gasket 26 formedby a reaction injection molding encapsulation process as disclosed inU.S. Pat. Nos. 4,561,625; 4,755,339; and 4,839,122, which areincorporated herein by reference. The single gasket 26 extends about theperiphery of the assembly and includes bottom and top segments 28, 30and side segments 32, 34. In addition, the single gasket 26 includes thetwo internal vertical segments 36, 38, all of the segmentssimultaneously and integrally formed during the reaction injectionmolding process of fixed glass windows 20, 22.

In general, the reaction injection molding process includes placing theindividual components in FIG. 2 into a mold (not shown). When the moldis in the open position, the two fixed glass windows 20 and 22 arepositioned on the lower section of the mold. The bottom and top brackets16, 18 are then positioned in the lower section of the mold. Seals areplaced throughout the molds in a known manner such that the sealscooperate with selected portions of the fixed glass windows 20, 22; thebrackets 16, 18; and the mold sections to define the gasket formingcavities. The cavities communicate with an inlet means or gate forreceiving a flowable polymeric gasket forming material from a nozzlemember. The gasket forming material is adapted to polymerize and cure insitu on the peripheral portions of the fixed glass windows 20, 22 andthe brackets 16, 18. The gasket may be formed by a reaction injectionmolding process using an elastomeric material such as polyurethane, forexample.

The brackets 16, 18 are positioned in spaced apart relationship with theinner surface of the horizontal edges of the fixed windows 20, 22 andsecured thereto by the gasket segments 28, 30. In the presentapplication, "inner" surface refers to the surface of the window orbracket facing the inside of the vehicle after the backlite windowassembly 14 has been mounted in a body panel. Conversely, the "outer"surface refers to the surface facing the outside of the vehicle afterinstallation.

After completion of the reaction injection molding encapsulationprocess, the window assembly 14 is ready for insertion of the slidingglass 24 with handle mechanism 40, and installation of the completedwindow assembly 14 into the body panel of a vehicle. The reactioninjection molding process results in a integral molding along allperipheral edges. The molded corners of the window assembly provide abetter seal than the overlap corners used in backlite assemblies in theprior art.

The fixed windows 20, 22 and the sliding window 24 are standardautomotive type glass with optional tinting and other sun screencapabilities. The brackets 16, 18 are generally U-shaped inconfiguration with the open sides of the channels 42, 44 facing eachother for acceptance of the sliding glass 24. The channel 42 for bracket16 is formed by inner and outer side walls 46, 48 and bottom segment 50.The channel 44 for bracket 18 includes inner and outer side walls 52, 54and top segment 56. Identical cams 58 are formed in the inner side walls46, 52 of the brackets 16, 18.

FIGS. 3, 4, and 4A show the sliding glass window 24 and the guides 60secured to the bottom and top edges 62, 64 of the sliding glass window24. The guides 60 include a flexible spring arm 66, a base 68, and avertical actuator surface 70 with tapered edges 72. The guides 60 aremade from a polymer material with sufficient resiliency to maintain thenecessary spring force.

When positioned in channels 42, 44, the spring arm 66 of the guides ispartially compressed to ensure the proper tension engagement in thechannels 42, 44. The spring arm 66 engages the outer side wall 48, 54,and the actuator surface 70 engages the inner side walls 46, 52 of thebrackets 16, 18. The spring arm 66 has a rounded head 74 to facilitatethe sliding movement in the channels 42, 44.

The guides 60 are positioned such that the actuator surfaces 70 engagethe cams 58 when the window 24 is in a closed position. The spring arm66 is fully compressed in the closed position and the slidable windowengages the segments 28, 30, 36, 38 of gasket 26 with sufficient forceto form a seal around all four edges of the slidable window 24. When thesliding window 24 is moved to an open position, the spring arm 66 isonly partially compressed. The force of the spring ann 66 expanding froma fully compressed position in the channels 42, 44 provides sufficientforce to move the sliding glass window 24 away from the gaskets topermit improved sliding of the window 24. The force of the partiallycompressed spring arm 66, however, is still sufficient to hold thewindow 24 in tension to eliminate rattles caused by vibrational movementof the sliding window 24.

The bottom and top edges 62, 64 of the sliding window 24 may include twoor more guides 60 in spaced-apart relationship on each edge. The guidemay also be formed in an elongate fashion such that only a single guidemay be used to facilitate the movement of a sliding window 24.

In the closed position, when the actuator surfaces 70 of the guides 60engages the cams 58, the sliding window 24 is compressed against thegasket segments as noted above. The polyurethane gasket 26 restricts themovement of the sliding glass window 24 such that up to 20 pounds offorce may be needed to move the sliding glass window 24 the finaldistance to close the sliding window 24. In an effort to reduce theclosing force required to slide the window 24 to a fully closedposition, the handle mechanism 40 is designed to provide additionalleverage to close the window 24.

The handle mechanism 40 includes a fixed base 76 attached to thevertical gasket 38. The fixed base 76 is provided with a groove 78formed in the base 76 which extends into sliding base 80. The slidingbase 80 is provided with an angle arm 82 pivotably connected to the base80 at pivot point 84. Rotating the handle 86 about the pivot point 84causes the tracking head 88 to move from a locked, close position to anopen position and vice versa. The handle mechanism 40 provides theadditional leverage needed to overcome the closing force of the window24 when the actuator surfaces 70 of the guides 60 engages the cams 58 inthe closed position.

Other styles and configurations of handle mechanisms 40 may be used ifsufficient force is generated to close the sliding glass window 24. Inaddition, other styles and configurations of guides 60 may be used tocreate the proper forces to seal the edges of window 24 in the closedposition, and to force the window 24 away from the gaskets 28, 30, 36,38 for improved sliding of the window 24 while maintaining the desiredstability in the channels 42, 44.

After the reaction injection molding process is complete, the slidingglass window 24 with guides 60 must be positioned between the bottombracket 16 and the top bracket 18. The sliding window 24 may bepositioned between the brackets 16 and 18 in the RIM molds such that nogasket forming material is deposited and cured on the sliding window 24.Another means of installing the sliding glass window would be totemporarily flex open the inner side walls 46 and 52 of the brackets 16and 18 and to wedge the sliding glass window 24 in place. FIG. 6 shows agap 90 formed in bracket 16 by removing a segment of the inner side wall46. The window 24 may be inserted into the brackets 16, 18 at the gap 90and slid into position. The sliding glass window 24 may also beinstalled from one end of the brackets 16, 18 by temporarily removinggasket 34 from the ends of the brackets 16, 18 to facilitate theinsertion of the sliding glass window 24.

The completed window assembly 14 is shown in greater detain in FIGS.7-10. The gasket 26 includes a notch 92 on the inner edge of the gasket26 for seating the assembly 14 in a side panel of a pickup truck (notshown). The outer surface 94 of the sliding window 24 engages the tip 98of lip 96 formed in gasket 26 about the aperture between the fixedwindows 20, 22. The lip 96 is formed on all four sides of the apertureand provides an excellent means for sealing the aperture so long as theforce of the sliding window 24 is sufficient to sealing engage lip 96.The gasket 26 may have different body configurations in varioussegments, such as the bottom gasket segment 28 shown in FIG. 10 and thetop gasket segment 30 shown in FIG. 9. However, the lip 96 provides thesame sealing affect around the periphery of the aperture between the twofixed windows 20, 22.

The lip 96 is integrally formed with the gasket 26 during a singlereaction injection molding process. The lip 96 is formed on the fulllength of the vertical gasket segments 36, 38 and on the center portionsof horizontal gasket segments 28, 30. Because no separate sealing piecesare required to be inserted in an additional channel and sealed in suchchannel, the integrity of the seal in the present invention is superiorto seals in the prior art. In addition, the labor and material needed toprovide an acceptable seal is substantially reduced.

In FIG. 7, the positioning and relationship of the cams 58 and theguides 60 are shown. The cams 58 urge the sliding glass 24 toward thelip 96 to completely seal the aperture between the fixed windows 20, 22.The lip 96 is formed from an elastomeric material which has sufficientflexibility and resiliency to exert a pressure to seal the perimeter ofthe aperture without breaking the sliding window 24, and to maintain thedesired seal over an extended period of operation.

FIGS. 8-10 show the positioning of the guides 60 in brackets 16, 18, andthe engagement of the gasket lip 96 and the outer surface 94 of thesliding window 24. The lip 96 formed on the bottom and top 28, 30segments of gasket 26 is the same configuration as the lip 96 on thevertical segments 36, 38 of the gasket 26.

The guide 60 engages the outer wall 48, 54 and inner wall 46, 52 of therespective channels 42, 44. When the sliding window 24 is closed, theguide 60 engages the cam 58 to urge the window 24 towards the lip 96 tocompress the spring arm 66 and increase the seal between the lip 96 andthe window 24.

When the sliding window 24 is open, the guide 60 does not engage the cam58 and the spring arm 66 is only partially compressed to maintain theguide 60 in tension in the channels 42, 44. Such tension minimizes anyvibration or rattles as the vehicle is being driven. The tension forceis transverse to the sliding path of the window 24. Consequently, thespring tension of the guides 60 does not restrict the sliding of thewindow 24 or increase the sliding force required to slide the slidingwindow 24.

As the force of the sliding window 24 against the lip 96 increases toincrease the integrity of the seal, the force required to slide thewindow 24 also increases. Consequently, the cam 58 is positioned suchthat the extra force to seal the aperture is applied only after theleading edge 104 of the sliding window 24 has cleared the lip 96 ofvertical gasket segment 38 as the window 24 is being closed. As aresult, the extra force is added only at the point of closing.

When the window is opened and the guide 60 disengages the cam 58, thespring arm 66 pushes the sliding window 24 away from the lip 96 toreduce the force needed to slide the window 24 along the range of openpositions.

The design parameters effecting the sealing forces and the slidingforces, such as spring force of the guide, the width of the channels,and the length and shape of the lip, can be adjusted to achieve thedesired sealing and sliding performance characteristics using the singlegasket formed by a single reaction injection molding process. FIGS. 10and 10A show two configurations of the bottom bracket 16. FIG. 10 is thecam 58, guide 60 and lip 96 shown in FIGS. 4-9. In FIG. 10A, the bracket106 has a narrower channel 108 and a guide 110 with no or very littlespring. The cams 112 have been significantly reduces in size. Theoverall tighter fit of the sliding window 100 in the channel 108 mayreduce rattles and provide a tighter seal, but the required force forsliding the window is increased.

In order to reduce the sliding force, the tip 114 of the lip 96 had beenrounded. A lubricant can be added to the lip 96 or the outer surface 102of the window 100 to reduce the required sliding force to open thewindow 100. Various coatings may be applied to outer surface 102 ofwindow 100 or the lip 96 in a standard production process. Silicon basedcoatings and other slip coatings are known in the art.

As shown in FIG. 10, the bottom bracket 16 includes a drain provision116 for directing any water to a plurality of miniature weep holes 118in the drain 116. Because the present invention does not require arubber gasket or other full length guide in the channel 42, the weepholes 118 can be positioned at appropriate intervals and can be makesignificantly smaller to reduce wind noise which can occur at the drainholes.

In FIGS. 11-13, the impact of the cam action at the closing point isshown in greater detail. The single, RIM encapsulated gasket segment 38of gasket 26 is secured about fixed window 22. The actuator surface 70engages the cam 58 to compress the spring arm 66 when the window 24 isclosed. The lip 96 of both the vertical gasket segment 38 and the bottomgasket segment 28 engages the outer surface 94 of the window 24. Whenthe window is opened and the actuator surface 70 clears the cam 58, thespring arm 66 forces the window away from the lip 96 to reduce thefrictional force of the window 24 sliding against the lip 96. The springeffect is highlighted in FIG. 13 by showing a slight gap 120 along theouter surface 94 of the window 24. In actual operation, the window 24will remain in contact with the lip 96, but with substantially lessengagement force in the open position.

Some vehicle manufacturers still prefer a discrete rubber gasket forsealably engaging the sliding window in a backlite window assembly.FIGS. 14-16 show an additional embodiment having a discrete sealingmember 132 for inclusion in a assembly 130 (shown only in fragmentaryviews of FIGS. 15-16). The brackets 16, 18; the fixed windows 20, 22;the sliding window 24; and the brackets 60 shown in assembly 14 andassembly 130 are identical and the same reference numbers are used inboth embodiments. The primary differences between the first and secondembodiments are the addition of a discrete sealing member 132 and achange in the configuration of the gasket 138, 140 about the aperture inthe assembly 130 in the second embodiment.

The sealing member 132 is typically made from rubber or other similarsealing material. The sealing member includes a body portion 134 and anextended lip 136. The extended lip 136 is similar in function to the lip96 formed by the encapsulated gasket of window assembly 14.

In window assembly 130, the reaction injection molding process includesthe proper positioning of the sealing member 132 in the mold. Thesealing member 132 defines the aperture in window assembly 130.

The encapsulated gasket is formed in a single reaction injection moldingencapsulation operation. The resulting gasket is a one-piece gasketformed about the periphery of the window assembly 130 and the aperturebetween the fixed windows 20, 22. The one-piece formation provides aunitary gasket which significantly reduces leakage problems.

The main difference between the gasket in the second embodiment and thegasket in the first embodiment is in the segments around the aperturebetween the fixed windows 20, 22. The gasket includes a vertical segment138 to sealably join the sealing member 132 and the fixed windows 20,22. The horizontal segments 140 of the gasket sealably join the sealingmember 132 to the brackets 16, 18.

The reaction injection molding encapsulation process eliminates the needfor a two channel bracket and improves the seal about the aperture.

In addition to the reaction injection molding process for forming apolyurethane gasket, other molding processes and materials can be usedto form the gasket. An elastic polyvinyl chloride material could be usedto form a gasket for the window assembly of the present invention.

In accordance with the provisions of the patent statutes, the presentinvention has been described in what is considered to represent itspreferred embodiment. However, it should be noted that the invention canbe practiced otherwise than as specifically illustrated and describedwithout departing from its spirit or scope.

What is claimed is:
 1. A window assembly provided with a sliding windowfor opening and closing an aperture in the window assembly, saidassembly comprising:a pair of windows in planar, laterally-spaced-apartrelationship, each window having an inner surface, an outer surface, anda peripheral edge; a pair of channel brackets adjacent the inner surfaceof said pair of windows, said brackets positioned in parallel,spaced-apart relationship and including a top bracket having alongitudinal channel extending along a top edge of said pair of windows,and a bottom bracket having a longitudinal channel extending along abottom edge of said pair of windows; a gasket integrally formed aboutthe peripheral edge of each window and adhering to an outer surface ofthe top and bottom channel brackets for securing said pair of windows tosaid pair of channel brackets, said gasket defining a periphery of saidwindow assembly and a generally rectangular aperture intermediate saidpair of windows in said window assembly; a sealing lip integrally formedin said gasket about the periphery of the rectangular aperture in thewindow assembly; and a sliding window positioned in the channels of saidchannel brackets for closing and opening the aperture in the windowassembly, said sliding window including an outer surface for engagingsaid sealing lip to seal the aperture in the window assembly when saidsliding window is in a closed position.
 2. The window assembly definedin claim 1 including at least one channel guide mounted on a top edge ofsaid sliding window and at least one channel guide mounted on a bottomedge of said sliding window, said channel guides positioned in thechannels of said brackets and including a spring means for engaging aninside wall and an outside wall of the channels for maintaining saidsliding window in tension in the channels and in engagement against saidsealing lip.
 3. The window assembly defined in claim 2 wherein thechannel in said brackets includes at least one cam formed in the innerwall of the channel for engaging the channel guide when said slidingwindow is in the closed position, said cam urging the channel guideagainst the outside wall to compress the spring means and force saidsliding window against said sealing lip to increase the pressure of theseal about the aperture.
 4. The window assembly defined in claim 2wherein said sealing lip includes a surface lubricant to facilitate thesliding of the sliding window in said channel brackets while maintainingthe seal about the aperture.
 5. The window assembly defined in claim 2wherein said sliding window includes a surface lubricant on the outersurface of said sliding window to facilitate the sliding of the slidingwindow in said channel brackets while maintaining the seal about theaperture.
 6. The window assembly defined in claim 1 wherein said gasketis composed of a synthetic polymer, said gasket having been polymerizedin situ adjacent said windows and said channel brackets through reactioninjection molding to form a single integral gasket.
 7. The windowassembly defined in claim 6 wherein said gasket is formed of anelastomeric material.
 8. The window assembly defined in claim 7 whereinsaid elastomeric material is a polyurethane material.
 9. The windowassembly defined in claim 1 wherein said gasket is composed of apolyvinyl chloride material, said gasket being injection molded to forma single integral gasket.
 10. The window assembly defined in claim 1wherein the bottom bracket includes at least one weep hole in thechannel.
 11. The window assembly defined in claim 1 including a latchingmeans mounted on a vertical edge of said sliding window for engaging acomplementary latching means mounted on one of said pair of windows. 12.The window assembly defined in claim 11 wherein said latching meansincludes a lever arm for closing said sliding window to sealably engagesaid sealing lip.
 13. A window assembly provided with a sliding windowfor opening and closing an aperture in the window assembly, saidassembly comprising:a pair of windows in planar, laterally-spaced-apartrelationship, each window having an inner surface, an outer surface, anda peripheral edge; a pair of channel brackets adjacent the inner surfaceof said pair of windows, said brackets positioned in parallel,spaced-apart relationship and including a top bracket having alongitudinal channel extending along a top edge of said pair of windows,and a bottom bracket having a longitudinal channel extending along abottom edge of said pair of windows; at least one cam formed in each ofthe channel brackets; a gasket integrally formed about the peripheraledge of each window and adhering to an outer surface of the top andbottom channel brackets for securing said pair of windows to said pairof channel brackets, said gasket defining a periphery of a windowassembly and a generally rectangular aperture in the window assembly; asealing lip integrally formed in said gasket about the periphery of therectangular aperture in the window assembly; a sliding window positionedin the channels of said channel brackets for closing and opening theaperture in the window assembly, said sliding window including an outersurface for engaging said sealing lip; and at least one channel guidemounted on a top edge of said sliding window and at least one channelguide mounted on a bottom edge of said sliding window, said channelguides positioned in the channels of said brackets and including aspring means for engaging an inside wall and an outside wall of thechannel for maintaining said sliding window in tension in the channel,said channel guide engaging said cam when said sliding window is in theclosed position, said cam urging the channel guide against the outsidewall to compress the spring means and force said sliding window againstsaid sealing lip to increase the pressure of the seal about theaperture.
 14. The window assembly defined in claim 13 wherein saidchannel guide includes two spaced-apart channel guides on the top andbottom edges of said sliding glass, said channel guides including aspring arm.
 15. The window assembly defined in claim 13 including alatching means mounted on a vertical edge of said sliding window forengaging a complementary latching means mounted on one of said pair ofwindows.
 16. A window assembly provided with a sliding window foropening and closing an aperture in the window assembly, said assemblycomprising:a pair of windows in planar, laterally-spaced-apartrelationship, each window having an inner surface, an outer surface, anda peripheral edge; a pair of channel brackets adjacent the inner surfaceof said pair of windows, said brackets positioned in parallel,spaced-apart relationship and including a top bracket having alongitudinal channel extending along a top edge of said pair of windows,and a bottom bracket having a longitudinal channel extending along abottom edge of said pair of windows; a sealing member defining arectangular aperture, said sealing member positioned in generally planarrelationship between said pair of windows and having a sealing stripextending about a periphery of said sealing member, said sealing stripprovided with an inward protruding lip extending about the periphery ofthe rectangular aperture; a gasket integrally formed about and adheringto the peripheral edge of each window, the periphery of the sealingmember, and an outer surface of the top and bottom channel brackets forsecuring said pair of windows, said pair of channel brackets, and saidsealing member as an integral window assembly having a rectangularaperture, said gasket defining a periphery of the window assembly; and asliding window positioned in the channels of said channel brackets forclosing and opening the aperture in the window assembly, said slidingwindow including an outer surface engaging the lip of said sealingmember to seal the aperture in the window assembly when said slidingwindow is in a closed position.
 17. The window assembly defined in claim16 including at least one channel guide mounted on a top edge of saidsliding window and at least one channel guide mounted on a bottom edgeof said sliding window, said channel guides positioned in the channelsof said brackets and including a spring means for engaging an insidewall and an outside wall of the channels for maintaining said slidingwindow in tension in the channels and in engagement against the lip ofsaid sealing member.
 18. The window assembly defined in claim 17 whereinthe channel in said brackets includes at least one cam formed in theinner wall of the channel for engaging the channel guide when saidsliding window is in the closed position, said cam urging the channelguide against the outside wall to compress the spring means and forcesaid sliding window against the lip of said sealing member to increasethe pressure of the seal about the aperture.